a. Field of the Invention
This invention relates to a test sample color comparison device used in biochemical examinations such as urine sugar, blood sugar, urobilin and other such examinations. The color comparison device contains a plurality of color reference shades which are sequentially compared to a color of a test stick reagent portion which has been impregnated, for example, with blood, in order to determine which of the color reference shades best matches the color of the reagent portion. The color shade which best matches the color of the test paper provides an indication of a biochemical condition, for example, the amount of sugar in the blood.
b. Discussion of Related Art
FIG. 3 (perspective view) and FIG. 4 (cross-sectional view) show a color comparison device on which the present invention improves. Specific details of this device are disclosed in Japanese Application No. 62-310246 and U.S. application Ser. No. 268,561 filed Nov. 8, 1988, the disclosure of Ser. No. 268,561 is incorporated herein by reference.
Another related color comparison device is also disclosed in U.S. application Ser. No. 224,367 filed July 26, 1988, the disclosure of which is also incorporated herein by reference.
The color comparison device of FIGS. 3 and 4 comprises a casing unit 1 which includes: an insertion section in the form of a test stick insertion groove portion 13 for removably receiving a color test paper portion 51 of a test stick 5: a protruding display section 11 for displaying the results of a color comparison; a manipulable rotatable wheel 2 rotatably fitted on the protruding display section 11 of the casing unit 1; a comparison color sample section 21 attached to the upper surface of the manipulable wheel 2 and having a plurality of staged reference color shades arranged in a circular array; a plurality of converter switches K mounted on the casing unit 1 in registry with the wheel 2 which convert the results of a visual comparison between the comparison color sample section 21 and the color test paper portion 51 into electrical signals representing the color shade on the wheel 2 which best matches the color of the test paper portion 51; an uneven patterned code section 4 integrally mounted on the underside of the wheel 2 and having an uneven pattern (defined by thickened portions 41 and thinned portions 42) corresponding to the staged color shades of the comparison color sample section 21 so as to operate the converter switches K as wheel 2 rotates; and a display means 14 (composed of a CPU and other electronic components) for displaying in a display section 17 the significance represented by the color shade which best matches the test paper portion 51 as designated by the converter switches K.
When a test sample color comparison is to be carried out using the above color comparison device, the test stick 5 is inserted into the stick insertion groove portion 13. In this condition, the color test paper portion 51, passed through a stick insertion inlet portion 35, is viewed through a comparison window 33 and overlies the comparison color sample section 21 of wheel 2 in registry therewith. In this condition, the manipulable wheel 2 is angularly moved (rotated) so that the color of the color test paper portion 51 can be visually compared with the staged color shades on the color sample section 21 as wheel 2 rotates to determine which color shade is the closest to the color of the test paper portion 51. As the wheel 2 is rotated, the comparison color sample section 21 underlying the color test paper portion 51 is also rotated as is underlying uneven patterned code section 4, mounted on the underside of the wheel 2, so that the plurality of converter switches K underlying the uneven patterned code section 4 in registry therewith are turned on or off in accordance with rotation of wheel 2. As a result, an electrical signal representative of the selected color shade which underlies the test paper portion 51 at any given time is generated by the converter switches K so that a signal representing the selected color shade which then underlies and best matches the color of the test paper portion 51 is generated in accordance with the states (ON or OFF) of the converter switches K. The significance (for example, the amount of blood sugar) of the selected color shade is displayed in the display section 17 through a memory means which stores the significance of the color shades for different angular positions of wheel 2, as determined by the electrical signals generated by converter switches K.
In the color comparison device of FIGS. 3 and 4, a stick insertion groove portion 13 of predetermined depth is provided in the upper surface of the casing unit 1 at one end portion thereof at a position centrally of the width of casing unit 1. The stick insertion groove portion 13 communicates with the comparison window 33, through which the comparison color sample section 21 can be viewed, through the stick insertion inlet portion 35 which is provided at one end of a cover unit 3 fitted on the casing unit 1. The cover unit 3 contains a window 34 for viewing display 17. The bottom surface of the stick insertion groove portion 13 is flat as shown in FIG. 4 and lies flush with the upper surface of the comparison color sample section 21. Therefore, when the test stick 5 is inserted into the stick insertion groove portion 13, with the color test paper portion 51 provided at the leading end portion, the leading end passes through inlet portion 35 and becomes vertically registered with the comparison window 33; that is, the color test paper portion 51 is disposed over the upper surface of the comparison color sample section 21, and the test stick 5 is disposed horizontally.
In this inserted condition of the test stick 5, it is disposed horizontally in a space between the cover unit 3 and the comparison color sample section 21, but it is not held or fixed to the display device. It has been found that this arrangement may suffer from disadvantages in use, one such disadvantage being that if the casing unit 1 is tilted during the color comparison operation, the test stick 5 can be accidentally disengaged from the casing unit 1.